EDIT: For lore reasons, I was also wondering if Anacreon has a backstory of any kind? The code seems to indicate these empires are all comprised of humans only, which leads one to believe alien species/nonhumans don't exist in this universe. The new game start text refers to an "Aelion Empire" which collapsed and possibly fragmented into many smaller empires.

Out of curiosity, I Googled some things and apparently Anacreon is a world in the Foundation Series universe by Isaac Asimov. Long story short, the Foundation preserved the technology and knowledge of the First Galactic Empire (Aelion Empire?) when it fell, and shared it with the new empires which rose up from its ashes (much like the foundations in game) Interesting, eh?

Also a few of the ship names, and weapon types seem to be taken directly from Transcendence, IDK if that's intentional or not...

Name recycling is pretty common, haha. The warlord empire "Efreet" is also an alien race in Transcendence.

I'm not sure how much is retained from them, but in earlier versions, aliens were a part of the game. Alien worlds meant your citizens would sometimes be killed at night by the locals, or more rarely, they would join your troops as particularly strong soldiers.

Fallen Worlds is the same scenario as the Reconstruction: 4021 scenario in Anacreon 1+2, but different scenarios have different backstories. Presumably scenarios take place at different times or different points in the galaxy (real galaxies aren't really rectangular planes, so I think there's space). These scenarios would all have different backstories, but the core universe stuff should be consistent across them.

Project Renegade (Beta) : "The Poor Man's Corporate Command!"
"Cowards die many times before their deaths; The valiant never taste of death but once. " -Julius Caesar as written by William Shakespeare, a notorious permadeath player.

"Anor Kingdom", "Imryrr Empire", "Kingdom of Johenna", "Muriel Union", "Olos Guaran" all existed in Beta II from the start. People gradually figured out that they were NPC empires because they didn't do anything but didn't auto-abdicate (similar to secession empires). A few of them got conquered but mostly they were so small that nobody bothered.

They have no code in their AI block so AFAIK they don't actually do anything other than sit there.

Anacreon: R4021 is strongly influenced by the Foundation books. Some of the 3rd party scenarios are influenced by (or baldly copy) Fred Saberhagen's Berserker series, which was big in the 1970s and 1980s. Anacreon arose from the same milieu with the play by mail (later play-by-email) game Starweb which also appropriated elements of the Berserker series. Many of the games in that strategy genre at that time share fictional DNA.

The original Anacreon had a sort of backstory in the manual and each scenario file included introductory text that explained the history and current state of the region of space that the scenario took place in, similar to the explanatory text to Fallen Worlds. Additionally, some individual worlds also had descriptive text that you could see when you conquered them.

For example, here is the descriptive text for the iconic "Pirates of Jakarta" scenario:

The reign of chaos that swept the stars burst upon the galaxy unannounced
and uninvited. The power of a thousand worlds pushed and pulled without
direction; powerless against the spreading revolution, only accelerating the
fall. By the year 3651, those sectors untouched by war were either
overflowing with refugees, plagued by marauders, or simply barren and
lifeless.
This scenario recreates the situation in the Charlatt sector during the
years 3651-3700. A commercial mining center on the upper half of the
Tyreemean Arm, the Charlatt sector was far enough from the Spinward Alliance
to escape its tyrannous expansion but close enough to be caught in the
whirlpool of its collapse. In the year 3428 the administrative center and
capital of the sector was destroyed by a cataclismic internal war. Although
most historians believe that the war was a clash between loyal elements of
the First Empire and the Isolationists, there is some evidence linking the
mysterious world of Jakarta with the catastrophe. Hidden in a shroud of
nebulous gas, Jakarta was the capital of a marauder empire. With the sector
capital reduced to nuclear ashes, the Pirates of Jakarta were free to prey
on lightly defended transport fleets throughout the entire region.
It is the year 3451. Without goal or guidance, the worlds of the Charlatt
sector have abandoned interstellar trading and are concentrating on
supporting their own people. You must rebuild the network of supply and
consumption that once produced enough metals for an entire arm of the
galaxy. You must unite the worlds of the sector and bring order to a region
now ruled by fear and destruction. And you must find and destroy Jakarta;
the eye of the storm, perhaps the only center of power to oppose you. All
you need is time to build and to re-unite. But Jakarta will not wait...

And then within the game you could find the following descriptions (please forgive me for spoiling a 30-year-old game scenario):

History: This world, now known as "Jerhad" by the local inhabitants,
was once the main military base of the Charlatt sector. Though little is
known about the wars that destroyed it, many historians believe that this
world led a revolution against the representatives of the First Empire.
Although the surface of the planet was reduce to rubble in the war, about
5000 penetrators of the 7th Arm of the United Charlatt Fleet were left
behind.
History: This world, now known as "Jerhad" by the local inhabitants,
was once the main military base of the Charlatt sector. Though little is
known about the wars that destroyed it, many historians believe that this
world led a revolution against the representatives of the First Empire.
History: Until it was destroyed in 3428, this world served as the adminis-
trative and commercial capital of the entire Chartlatt sector. Though the
surface of the planet is now completely uninhabitable, pockets of high-
technology civilization have survived in shielded underground cities.
Description: Jakarta is a world of stark contrasts. The bright blue skies of
this world blanket a barren wasteland of lava flows and magma pits. Although
there are pockets of civilization on the surface, most of the population
lives in ancient orbiting cities. Little is known about the culture of the
Jakartans, as they seldom allow visitors.
Description: Once a productive trillum mine, this world was ravaged by war
when the supply routes collapsed. Although some limited trade still goes on,
many fear the Jakartan pirates. Rumors here also speak of a network of
jumpspace mines in the veil of the nebula.
Description: This is one of the few worlds in the sector truly hospitable to
human life. Although this world can produce the large quantities of supplies
needed by other more barren worlds, few traders enter or leave the system
for fear of the pirates. Some traders claim that they have seen the pirate
capital at [C2:3], not far from here.
Congratulations, Your Majesty, you have conquered Jakarta! Ground assault
troops have taken control of the planet and report that they have captured
the Jakartan leaders.
Fleet commander report: "...Target has surrendered, all internal opposition
neutralized. Records on the planet dating back to 3515 indicate that part of
the old Charlatt fleet was left in orbit at [C2:5]. It is possible that we
may find some ships there...(end report)"

This was a small two-player scenario with a fairly functional Pirate AI empire, a clear win condition and a lot of descriptive text. The goal was to be the first player to defeat the AI empire. DOS Anacreon had 5 or 6 different AI empire types. The "Pirate" AI had a specific region of space that it would treat as its "hunting ground" and I believe that it attacked transport fleets and raided worlds that players were foolish enough to settle in (trade routes required actual transport fleets moving around, and fleets could be intercepted and destroyed/captured in deep space).

I played partway through this scenario using the Windows Anacreon port with RPC a couple years ago.

One way that interesting "NPEs" could be added without writing any AI code would be to scatter a bunch of single-planet independent worlds that have a special "barter world" designation allowing them perform reciprocal demand:max trade for specific resources with T&E empires at advantageous rates. They would either not participate in the AE economy, or only give/receive aes for their specific resources.

Imagine for example a world that is not part of your empire, but to which you can establish a trade route to that trades consumer goods for light jumpdrives at a decent exchange rate (the barter exchange structure on the independent world would convert WUs + your resource into the other resource, so you would not be able to convert an infinite amount, just as many as the world can handle). Now your T&E empire doesn't have to add a jumpship autofac to build jumpmissiles, which would help you stay under the 100-world limit.

Since these worlds would not be part of an empire, there should be no penalty for capturing them, but they would lose their barter world designation when captured (they would also need to remember that they are barter worlds and reclaim that designation when they go independent, or capturing them should give an option to release them as an independent planet). Thus, trade could endure in the galaxy even if the Mesophon trader empire gets destroyed, and T&E empires would not be as burdened by defending their trade partners since they would be able to reactively liberate barter worlds conquered by other empires rather than being forced to protect them lest they be lost forever.

If units could be exchanged via a trade route, this could also be a great alternative to purchasing units from Mesophon- instead of instantaneous purchases, you get a trickle over time. This could be a way for T&E empires to get infantry or planetary defense without building them themselves, allowing them to reduce overhead and remain laser-focused on trade good production within their 100-world limit.

It is interesting that you say the NPC Empires have no code for AI. Sometimes I would lose worlds to them. I have kept track of a few who lost their capitals due to invasions by new players, eventually the NPC Empires gained a capitol back. Maybe taking their capitol means nothing. Another strange event was about 40 relients with a few troops were invading some world with the NPC's designation. Also, I think Watch TV mentioned he had found improved worlds that had become Mesophone Worlds, which I am guessing should not happen if Mesophone was not active. This gave us the impression George or team members were playing. Curiously there doesn't seem to be any occurrences of this type of NPC activity until the weirdness with the Nebula's that happened last fall I believe.